There's no shame in admitting that Anderson Silva has sub-par take down defence. He more than makes up for it with a great submission game. To act as though Chael Sonnen is the only man to take Anderson down and control him from the top is inaccurate. Henderson, Lutter, and to a lesser extent, Okami all managed the same. People who work to take Anderson down are likely to be successful. Whether or not they get submitted is another story.